title: Chemical and genetic validation of thiamine utilization as an antimalarial drug target.
abstract: Thiamine is metabolized into an essential cofactor for several enzymes. Here we show that oxythiamine, a thiamine analog, inhibits proliferation of the malaria parasite Plasmodium falciparum in vitro via a thiamine-related pathway and significantly reduces parasite growth in a mouse malaria model. Overexpression of thiamine pyrophosphokinase (the enzyme that converts thiamine into its active form, thiamine pyrophosphate) hypersensitizes parasites to oxythiamine by up to 1,700-fold, consistent with oxythiamine being a substrate for thiamine pyrophosphokinase and its conversion into an antimetabolite. We show that parasites overexpressing the thiamine pyrophosphate-dependent enzymes oxoglutarate dehydrogenase and pyruvate dehydrogenase are up to 15-fold more resistant to oxythiamine, consistent with the antimetabolite inactivating thiamine pyrophosphate-dependent enzymes. Our studies therefore validate thiamine utilization as an antimalarial drug target and demonstrate that a single antimalarial can simultaneously target several enzymes located within distinct organelles.
authors.affiliation: Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Xie Wah Audrey
authors.initials: XW
authors.lastname: Chan
authors.forename: Carsten
authors.initials: C
authors.lastname: Wrenger
authors.forename: Katharina
authors.initials: K
authors.lastname: Stahl
authors.forename: Bärbel
authors.initials: B
authors.lastname: Bergmann
authors.forename: Markus
authors.initials: M
authors.lastname: Winterberg
authors.forename: Ingrid B
authors.initials: IB
authors.lastname: Müller
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Saliba
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000962:Antimalarials / Q000737:chemistry / Q000494:pharmacology*; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D004912:Erythrocytes / Q000187:drug effects / Q000469:parasitology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D007655:Ketoglutarate Dehydrogenase Complex / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D010119:Oxythiamine / Q000737:chemistry / Q000494:pharmacology; D018512:Parasitemia / Q000201:enzymology / Q000378:metabolism / Q000469:parasitology; D010271:Parasites / Q000187:drug effects / Q000235:genetics*; D010766:Phosphorylation / Q000187:drug effects; D010963:Plasmodium falciparum / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015203:Reproducibility of Results; D013836:Thiamin Pyrophosphokinase / Q000378:metabolism; D013831:Thiamine / Q000737:chemistry / Q000378:metabolism*; D013835:Thiamine Pyrophosphate / Q000378:metabolism
chemical_list: D000962:Antimalarials; D011768:Pyruvate Dehydrogenase Complex; D012333:RNA, Messenger; D011994:Recombinant Proteins; D010119:Oxythiamine; D007655:Ketoglutarate Dehydrogenase Complex; D013836:Thiamin Pyrophosphokinase; D013835:Thiamine Pyrophosphate; D013831:Thiamine